The present invention relates to a disk drive, as well as an actuator and a head actuator assembly used in the disk drive.
Data storage devices using various types of media such as optical disks and magnetic tapes are known. Among them, hard disk drives (hereinafter referred to as HDDs) have become popular as storage devices for computers to such an extent that they are one type of the storage devices indispensable for today's computers. Further, not limited to computer systems, HDDs are expanding more and more in application because of its excellent characteristics. For example, HDDs are used for moving picture recording/reproducing devices, car navigation systems, cellular phones, and removable memories for use in digital cameras.
Each magnetic disk used in HDDs has a plurality of tracks formed concentrically and each track is divided into a plurality of sectors. Servo data and user data are stored in each of the sectors. A spindle motor rotates the magnetic disk and a head element as a thin film element makes access to a desired address position in accordance with the servo data stored in a sector, whereby it is possible to effect write or read of data to or from the magnetic disk.
The head element is fixed to a slider, both constituting a head. The slider is adapted to fly over a rotating magnetic disk, whereby the head or the head element can be moved to a desired position over the magnetic disk. In a data read operation, a signal read from the magnetic disk by the head element is subjected to predetermined signal processing such as waveform shaping or decoding in a signal processing circuit and is then sent to a host. Data transferred from the host is subjected to predetermined signal processing in the signal processing circuit and is then written to the magnetic disk.
In HDD, not only vibrations caused by rotation of the magnetic disk pose a problem (see, for example, Patent Document 1 (Japanese Patent Laid-open No. 10-320964)), but also satisfactory impact resistance to collision with an external object is required. As mentioned above, since the HDD is mounted in various products, it is required to exhibit impact-resisting performance appropriate for the product in which it is mounted. In particular, when mounted in a portable product such as a laptop PC or a digital camera, the HDD is required to possess high-impact resistance. In the actual manufacture of products, the HDD or an HDD-mounted product is dropped onto a floor surface to check the impact-resisting performance of the HDD.
On the other hand, downsizing of the slider is being promoted from the standpoint of reducing the size of the HDD, increasing the surface recording density, reducing the cost and improving the seek speed. The slider size is defined by IDEMA (International Disk Drive Equipment and Materials Association) Standards. More particularly, in descending order of size, mini sliders, micro sliders, nano sliders, pico sliders, and femto sliders are defined. Although pico sliders are most popular in the existing HDDs, it is presumed that femto sliders will be used in a larger number of HDDs in future.